Catalytic conversion of hydrocarbons



April 20, 1948.

.1. w. JEWELL .811

CATALYTIC CONVERSION OF HYDROCARBONS I 4 Shee ts-Sheet 1 Filed lay" 21, 1941 L m m J, c a E 5 H6 7 m .H J I. H .4 A R Wm m r 7 n iil NJ -MA. S m m 6% H B m- T m 5 s m L T E H c0 I 0 R m 9 mi 2, 5 Mr I awn Pa :2 9 m J P. J 3 a M n 7 a, am u a I ZMYL I- .1 w a i /mm a 5 v 0 4v Q "L April 20, 1948.

J. W. JEWELL' CATALYTIC CONVERSION OF HYDROOARBONS Filed lay kl, 19:41

1 FLUE ans 4 Sheets-Sheet '2 ATTORNEYS April 20,1948. J. w. JEWELL' 2.439311 CATALYTIC CONVERSION OF HYDROCARBONS Filed lay 21, 1941 4 Sheets-Sheet 3 A'ITORNEYS P 1943- .1, w. JEWELL 2,439,811

- CATALYTIC CONVERSION OF BYDROCARBONS Filed llay 21, 1941 4 Sheets-Sheet 4 FLU ans A47 im/236 27 I! W "J 2% JOSEPH. vv. JWLL INVENTO A'ITORN EYS Patented Apr. 20, 1948 CATALYTIC CONVERSION OF HYDROCABBONS Joseph w. Jewell, Summit, N. 1., assignor to The M. W. Kellogg Company, Jersey City, N. 3., a

corporation of Delaware Application May 21, 1941, Serial No. 394,440 Claims. (01. 196-52) The present invention relates to improvements in effecting chemical reactions involving the contact of gas or vapors with a solid in finely divided condition. More particularly, the invention pertains to improvements in the conversion of hydrocarbons such as the conversion of high boiling hydrocarbons to lower boiling products by contacting the high boiling hydrocarbons in the vapor phase with a catalyst in a state of line subdivision.

It has been proposed heretofore to catalytically convert high boiling hydrocarbons such as a petroleum gas oil to low boiling hydrocarbons Within thegasoline boiling range by passing va-' pors of the high boiling hydrocarbons under-suitable reaction conditions in contact with a stationary bed of a cracking catalyst. Pursuant to such processes, after the activity of the catalyst is decreased by reason of the formation of a carbonaceous deposit thereon to an extent where regeneration is necessary or desirable, the activity of the catalyst is restored by stopping the flow of oil vapor to the bed of catalyst and passingan oxygen-containing gas through the bed in contact with the spent catalyst, thereby regenerating it in situ by combustion of the carbonaceous deposit. Although such processes are commercially practicable they are subject to a number of inherent limitations and disadvantages. Among these are the intermittent nature of the operation, variations in product quality and quantity during the reaction period and difficulty in temperature control, particularly in the regeneration operation. a

A process whereby these objectionable limitations and disadvantages of the stationary bed or intermittent type of conversion operation arelargely eliminated is described in copending application Serial No. 390,164, filed April 24, 1941, in which applicant is a co-applicant. Pursuant to the latter process, the catalyst is introduced into the conversion and regeneration zones in finely divided or powdered condition and at the same time certain of the variable operating conditions are so controlled as to maintain a preferred concentration of thecatalyst in said zones for the desired conversion and regeneration effects. One of the distinctive features of the process is the maintenance of a relatively low velocity of the vapors passing through the conversion and 2 regeneration zones whereby a dense phase or mass of the catalyst is maintained inthese zones, In the case of the conversion zone, fresh catalyst is continuously added to said dense phase and,

corresponding amounts of used catalyst withdrawn therefrom at a rate adapted to maintain the average catalytic activity at a suitable value. Similarly, in the regeneration zone, spent catalyst is continuously added thereto and regenerated catalyst withdrawn therefrom. One of the most important features contributing to the satisfactory practice of such a process resides in the provision of an especially suitable method of separating the finely divided catalyst from the vapors or gases withdrawn from the conversion and regeneration zones. The present application is directed particularly to this feature of the process.

One method proposed for the separation of the catalyst from the mixture of gas and catalyst particles withdrawn from the conversion and regeneration zones involves withdrawing the mixture from said zones through a constricted outlet at a high velocity and passing it through cyclone separators to effect the desired separation under a relatively high vapor velocity condition. The present invention is based on the discovery that such methods of separation are not essential, and that the mixture withdrawn from the conversion and regeneration zones may be separated bv a substantially more effective and less expensive method and apparatus than the cyclone separators or similar systems operating under high velocity heretofore considered necessary.

' Pursuant to this invention, the gaseous mixture containing spent or regenerated catalyst withdrawn, respectively, from the conversion and regeneration zones, is passed into a separating zone of relatively large cross sectional area wherein at the required rate. An additional feature of the process in its preferred aspect resides in the withdrawal of the gas and catalyst mixture from the conversion and regeneration zones through a constricted outlet at a high velocity and imping ing it against a deflecting surface or baiile positioned in the separating zone, the baiiie being of a configuration especially adapted to facilitaie the formation of the desired two distinct phases. Various other features and advantages of my invention will be apparent from the following detailed description of exemplary embodiments thereof given in connection with the appended drawings, wherein:

Fig. 1 is an elevation view of the combined reactor and used catalyst separator and the combined regenerator and regenerated catalyst separator, and illustrates the details of these elements and their interconnection.

Figs. 2 and 3 are views similar to Fig. 1 of modifled embodiments of the invention Fig. 4 is an end elevational view of the assembly of regenerator separator and associated Cottrell precipltator.

Fig. 5 is a further modified embodiment of the invention.

Fig, 6 is a plan view further illustrating a preferred embodiment of the deflecting surface or baiille device.

Referring to Fig. l, a fine divided or powdered active catalyst is introduced through the outlet i of a catalyst standpipe 3i into a stream of the feed vapors traveling at a relatively high velocity through the reactor inlet line 2. Both the catalyst and vapors preferably are heated prior to their mixture in their line 2 to an elevated temperature suitable for the subsequent conversion.

vaporized feed may be supplied to line 2 by a transfer line 3 leading from a suitable source of vaporized feed stock such as a pipe still heater. Catalystthus introduced is picked up by the vapors and carried therewith through line 2 into a conical inlet 5 in the lower part of reactor 8. Reactor 6 is a vessel, in the form of a cylinder or other suitable shape, having a relatively great crosssectional area compared to the cross-sectional area of the vapor inlet line 2, and these relative proportions cause a corresponding reduction in the velocity of the vapors after their passage from inlet line 2 into the reactor 6. The velocity of the vapors in reactor 6 is preferably maintained within such limits as to produce a concentrated or dense phase of the catalyst which state may conveniently be designated as "fluidized" or pseudo-liquid. This fluidized condition, in general, is characterized by the relatively high concentration of catalyst measured in terms of the quantity of catalyst per unit volume of reactor space, and by the maintained low velocity of reactant vapors through the reactor.

The reactant vapors travel upwardly through the reactor in contact with the fluidized catalyst and during this period of contact undergo the desired conversion. Operating conditions in the reactor determined by variables such as the dimensions of the reactor, and the temperatures and rates at which reactant vapors and catalyst are supplied thereto, are maintained within such limits as to bring about the desired quality and extent of conversion as exemplified and described in detail hereinafter.

The vaporous reaction products are withdrawn from the upper part of reactor 6 through a constricted outlet zone. The vapors pass from the upper portion of the reactor into the conical outlet lof progressively decreasing cross-sectional area in the direction of flow wherein their but may be more or less than the vapor velocity in reactor 6. A deflecting surface or baflie l0, shown in plan in Fig. 6, is preferably interposed directly in the path of the vapor mixture exiting from pipe 8. The impinging surface of the bailie is preferably curved or is concave downwardly as shown so that the mixture is directed laterally and downwardly thus functioning to propel catalyst particles present in the mixture out of the path of the vapor flow into a quiescent collecting zone A defined by the outer walls of the outlet cone 1 and outlet pipe 8 and the lower inner walls of the settling or collecting hopper 8. The baiiie may be circular in plan or any other suitable shape. however, the embodiment shown in plan view in Fig. 6 is especially advantageous since the catalyst separates primarily along the longitudinal edges 40 of the deflecting surface and the vapor flows axially of the bailie to a large extent and leaves the deflecting surface at the ends ll thereof, thereby reducing the tend- -ency of the catalyst particles to become resuspended in the vapor. Catalyst thus separated is continuously withdrawn through suitable means such as catalyst standpipe il opening into the lower part of the collecting zone A. A quantity of catalyst is preferably left at all times in said zone to maintain a level of catalyst therein at a substantial distance above the spent catalyst outlet opening as indicated by dotted line l2 and at a substantial distance below the vapor inlet line 8. 'Vaporous conversion products withdrawn through line I3 contain a relatively small portion of the catalyst originally present in the mixture passing through pipe 8.

Residual catalyst left in the vaporous conversion products exiting through llne It to the products recovery system is separated in any suitable type of gas-solid separator such as the system of cyclone separators described in said application Serial No. 390,164 and may be returner: to the spent catalyst in zone A through line I A suitable inert aeriform medium such as I steam is introduced through lines I! having suitable fluid distributing means l6, in the bottom of the mass of catalyst in the collecting zone to maintain the mass in an aerated flowable condition and to strip or displace hydrocarbon vapors absorbed thereon or entrained therewith. While only two such lines It for introduction of the stripping medium are shown, it is to be understood that any suitable number may be employed and be so distributed throughout the collecting chamber as to assure the required stripping and aerating efiects. The quantity of stripping steam employed is preferably such that its velocity in the collecting zone is low, that is, of the order of about 0.1 to 0.3 foot per second. The medium thus introduced and stripped oil vapors pass out of chamber 9 overhead through line l3 together with the vaporous conversion products. 1

Asillustrative of operating conditions suit Team 1 Reactor 6 conditions and dimensions Gas oil feed (31.1 A. P. I. Mid-Continent gas oil) bbls./day 10,000 Steam feed, lbs/hr"--- 13,360 Reactor dimensions (a) ht.-ft 25 Reactor dimensions (2;) dia.-'-ft 12.5

Feed weight ratio of catalyst to oil 5 Reactor temperature, inlet cone -tiF 955 Reactor temperature, outlet cone 'l--F 900 Reactor pressure, inlet cone 5lbs./sq.

in g 13.0 Reactor pressure, outlet cone 'l--lbs./sq.

in 9.6 Vapor velocity, inlet, ft./sec 1.48 Vapor velocity, outlet, ft./sec 2.45 Ratio of weight of oil fed/hr. to wt. of

catalyst in reactor (w./hr./w.) 2.3 Oil vapor, contact time-seconds 13.6 Catalyst time-seconds 290 Catalyst concentration, lbs/cu. ft.:

(11) Inlet line 2 0.98 (b) Reactor 18.0 (c) Reactor outlet, line 8 0.6 Spent catalyst hopper 9 conditions and dimensions Hopper 0 (a) ht.-ft 34.8 Hopper e (b) dia.--ft 15.4 Outlet pipe 8', dia.-ft 4.5 Vapor velocity, outlet pipe 8ft./sec 20.0 Vapor velocity, hopper 9ft./sec 1.75 Catalyst concentration, collecting zonelbs/cu. ft 25.0 Per cent of used catalyst withdrawn through standpipe ii 95.0

In conveying the spent catalyst from the spent catalyst collecting zone A to the regeneration zone suitable provision is made for any dlf-l.

ference in pressure between these zones. A somewhat higher pressure is normally preferably maintained in the bottom or inlet portion of the regeneration zone than the pressure main tained in the collecting zone, and a head of suitably aerated or fluidized catalyst is preferably maintained in the outlet standpipe it of a sufficient magnitude to balance or exceed somewhat this differential pressure. For this. purpose spent catalyst flowing through standpipe I I is maintained in a condition in which it has the flow characteristics of a liquid by introducing in suitably regulated amounts an aerating medium such as steam through lines I! at the bottom of and at other suitably spaced points along the length of pipe II.

From the bottom of standpipe I I spent catalyst is fed under the influence of the'pressure head maintained therein and the pressure head provided by 'the mass through a suitable feeding means such as a valve I8 into the regenerator inlet line I9.

Spent catalyst thus introduced is mixed with airor other suitable carrying medium such as steam introduced into pipe I9 by line 20". In case air is employed, the quantity introduced is so controlled that the combustion'of the spent of catalyst in zone A- catalyst in line temperature of the catalyst beyond the maximum safe regeneration temperature.

introduced separately into regenerator 2i, I-may utilize to advantage a modified flow comprising the introduction of the mixture of cooled catalyst and air withdrawn from exchanger 22 into line 20' in place of directly to the reactor. Due to the presence of the cooled recycled mixture in line I 9, the possibility of an excessively high fiash" combustion temperature in line I9 is thereby obviated.

Operating conditions in the regeneration chamber or zone 2i are preferably maintained to provide a condition similar to that maintained in the reaction zone with respect toa "fluidized" condition of the catalyst. This condition similar to that maintained in the reactor is characterized by the relatively large concentration of catalyst and low vapor velocity maintained. During the course of the travel of the spent catalyst and air upwardly through regeneration chamber 2|, combustion of the carbonaceous deposit on the used or spent catalyst is efifected to the required extent at an elevated temperature maintained below the safe maximum regeneration temperature by means of the cooled recycled catalyst.

Gaseous regeneration products (flue gas) and regenerated catalyst exit from the upper part of the regenerator through a constricted outlet 23 and into a regenerated catalyst collecting hop-' per 24 similar in design and mode of operation to collecting hopper 9 described in connection with the reactor. The major portion of the regenerated catalyst is separated and collected in a collecting zone B at the bottom of hopper 2t,

Suitable means 21 and 28, similar to pipe i 5 and distributor I6, are provided in the lower portion of hopper 24 to introduce an inert aeriform medium such as steam to maintain the separated catalyst in an aerated flowable stateandstrip and displace flue gas absorbed or entrained with the regenerated catalyst. Again as in the case of the reactor, a level of separated catalyst indicated by dotted line 29 is preferably maintained at a substantial distance below the top of outlet 23 and above the catalyst outlet lines 30 and 3!.

Regenerated catalyst is preferably withdrawn from the collecting zone in hopper 24 in a split stream, a portion being sent through regenerated catalyst recycle line 30, and another portion through regenerated catalyst line 3i leading to the conversion or reaction system. Both catalyst outlet lines 30 and 3! are pressure standpipes, similar to standpipe II in that they are provided with means for introducing an aerating medium at suitable points along their length so 6 I9 is not sufilcient to raise. the

Catalyst recovered system from standpipe as to maintain the catalyst flowin therethroush in a condition wherein it has the flow characteristics of a liquid, such means being lines 32 leading to recycle line 30 and lines 33 leading to catalyst outlet line 3i. The quantity of catalyst withdrawn and recycled through line 30 is preferably maintained within predetermined limits so as to maintain the temperature in regeneration zone 2| within required limits in accordance with the principles of operation described in copending application Serial No. 274,670 (which issued as Patent No. 2,253,486 on August 19, 1941), and Serial No. 343,222, by Arnold Belchetz, filed May 20, 1939, and June 29, 1940, respectively.

Regenerated recycle catalyst is fed from the bottom of standpipe 30 through a suitable feeding means such as a valve 34 into an inlet line 35 leading to a heat exchanger or catalyst recycle cooler 22. Regenerated catalyst thus introduced is picked up by air introduced into line 35 through line 36, the quantity of air thus introduced being sufficient together with any air introduced through line 20 to effect combustion to the required extent in the regenerator 2|. From line 35 the mixture of air and regenerated catalyst passes through exchanger or cooler 22 wherein the temperature of the recycled catalyst is lowered by indirect heat exchange.

with a cooling medium circulated through the exchanger by lines 31 and 38.

Regenerated catalyst is fed to the conversion 3| through a suitable feeding means at the bottom thereof such as a valve 39 and line I into the stream of vapors to be converted passing throughline 2 as previously described.

To exemplify operating conditions preferably maintained in the regeneration zone 2! and separating zone 24, and suitable dimensions for these zones, reference is made to the data tabulated in the following Table 2 wherein such data are given for a regeneration stage corresponding to the conversion stage tabulated in Table l.

V 8 Regenerated catalyst hopper 24 conditions and dimensions Hopper (a) ht.-ft 27.5 Hopper (b) dia.-ft 21.75 Outlet pipe 23, dia.--ft 6.5 Vapor velocity, outlet pipe 23ft./sec 20.0 Vapor velocity, separator 24-it./sec 2.0 Catalyst concentration, collecting zonelbs./cu. it 25.0 Per cent of separated catalyst withdrawn through standpipes 30 and 3|- 95.0

In the modified embodiment of the invention illustrated in Fig. 2, elements generally corre sponding in their design and function to similar elements in Fig. l have been designated by corresponding numerals with the subscript c. Accordingly, detailed description of these particular elements is unnecessary. In this embodiment the vaporous mixture withdrawn from the reactor through constricted outlet 8a passes into one end of a horizontally extending separating zone to and the vapor inlet No is disposed at the opposite end portion of thiszone thereby providing for the horizontal travel of the mixture of catalyst and gas a substantial distance through the separating zone whereby the efilciency of the separation is enhanced. A similar gas-solid separating arrangement 24a is employed to separate the regenerated catalyst from the gaseous mixture of TABLE 2 Regenerator conditions and dimensions Spent catalystlbs./hr 632,840 Cooled recycled catalyst-lbs./hr- 1,750,000 Ratio by weight recycled/spent 2.77 Inlet temperature, spent catalyst, "F--- 900 Inlet temperature, recycled catalyst, "F 840 Temperature, mixture recycled and spent catalyst, 850 Temperature, regeneration chamber, F 1,000 Regeneration dimensions:

(a) Height, ft 50 (b) Diameter, ft -i 18 Renegeratlon velocity:

(a) Base 1.62 (11) Top 2.59 Air feed, lbs/hr 88,350 Catalyst concentration, lbs/cu. ft.:

(a) Regenerator 20.0 (b) Outlet line 1.02 Weight per cent of coke based on oil feed 4.85 Coke, per cent by weight on spent catalyst 1.3 Carbon, per cent by weight on regenerated catalyst.- 0.?- Catalyst contact time. seconds 35 Pressure in regenerator, lbs/sq. in:

(a) Inlet'cone 16 (b) Outlet cone .9

regenerated catalyst and flue gas withdrawn through the constricted outlet 23a.

Since the flow of the mixture of catalyst and vapor is in a horizontal direction in separator 9a and 24a, the vertical cross-sectional area of each separator is made sufficiently large that the vapor velocity therein is relatively low, corresponding to the low vapor velocity maintained in separator 8. A baiile l0a, corresponding to bathe l0, may be provided directly in the path of the vapors flowing at a high velocity from reactor outlet pipe 8a, thereby facilitating the separation of the mixture into the desired lower dense catalyst phase and upper dilute phase of vapors mixed with a relatively small quantity of unseparated catalyst. In the lower part of the separating zone, means Ilia are provided for introducing an aerating and stripping medium such as steam into the dense catalyst phase thereby maintaining it free of reaction product vapors and in a readily flowable condition. During the horizontal travel of the mixture through the separator, additional catalyst separates therefrom on to the dense catalyst phase and is carried to the outlet standpipe therewith. The eiilciency of the separation is thereby enhanced, the extent thereof depending upon the length of the horizontal path through the reactor. The upper levels i2a and 20a of the separated dense catalyst phase are maintained at a predetermined distance from the vapor outlets |8c and 25a, respectively, by continuous withdrawal of the dense catalyst phase through the discharge standpipes, the rate of discharge being controlled by the valve at the lower end of the standpi-pe. The distance between the upper level of the dense catalyst phase and vapor outlet in each instance is such as to reduce the quantity of catalyst withdrawn overhead to a relatively small percenta e of the catalyst present in the vapor mixture entering the separation zone. The dilute vapor phase exits from separator 0a through outlet 13a into a suitable gas solid separator such as a Cottreil precipitator 42. This precipitator may be of conventional design, in which the reaction vapors are withdrawn overhead through line 43 and separated solids at the bottom through a suitable hopper. Solids separated in precipitator B2 are returned to the lower dense phase by hopper Ma which preferably extends slightly below the upper level of the dense phase as shown. The separated spent catalyst is withdrawn from separator 9a through catalyst standpipe lia,to which a suitable aerating medium is supplied through lines Ila. Separator 26a for separating regenerated catalyst from the gaseous mixture withdrawn through the constricted outlet 23a is of a generally similar design and operates on principles similar to separator 9a. The only material difl'erence is in that in the regeneration stage, an alternative flow arrangement is illustrated wherein the constricted outlet 23:: terminates at the top of the separator and no bafiie is employed. 'Figure 4 is an end view of separator 24a and the associated Cottrell precipitator M, and shows the relationship between the vapor outlet 25a and hopper 25a for returning catalyst recovered in the Cottrell precipitatordt below the level of the dense catalyst phase.

Figure 3 illustrates a further modification similar to Figure 2 in all'material particulars except for the omission of the constricted outlets 8a and 23a leading from the conversion and regeneration zones, respectively, to the corresponding separators. Elements of this figure correponding in function to those of Figure 2 are identified with a similar numeral with the subscript b. In this embodiment the mixture of the vapors and catalyst withdrawn from the conversion and regeneration zones passes directly into theseparating zone with little or no intervening change in velocity by reason of the omission of the constricted outlet 8a and 23a.

Figure illustrates a further modification of the separator ofthe type represented by 9 and 24 in Fig. 1. Elements of Fig. 5 corresponding to those in Fig. 1 are indicated by similar reference numerals with the subscript c. In the embodiment shown in Fig. 5, an additional deflecting surface or bafiie 46 similar to baflie 450 is disposed in a series or tandem arrangement therewith, together with means for increasing the velocity of the vapor leaving the first baflle and impinging it at this increased velocity against the second baflie 66 These means comprise a hood M enclosing the first bafile dticand having its lowerperiphery extending below the level of the separated catalyst and terminating at its upper periphery in a high velocity outlet constituted by upwardly converging cone 8 and outlet pipe 49. Catalyst deflected from bafie 66 passes between the narrow annular space between hood 1 and inner walls ofhopper 24c and combines with previously separated catalyst from baifie 450.

In the practice of the invention operating conditions in the conversion and regeneration zones are preferably regulated as set forth in the above mentioned application, Serial No. 390,164, and particularly so as to provide a relatively dense or concentrated phase of the catalyst in these zones. To obtain this result low vapor velocities 'less than 6 ft./second and preferably less than4 ft.,

' second or less are contemplated. The range of vapor velocity ranges regarded as especially suitable is that extending from about 1.5 to about 2 ft./second.

It is to be understood that the various em- 10 thereon without departing from the essential features of the invention.

I claim: 7 y l. A process for the continuous catalytic conversion of hydrocarbons, which comprises continually effecting the following steps, introducinga catalyst in powdered condition toa catalytic conversion zone, flowing vapors of the hydrocarbons undergoing conversion upwardly through said zone at a velocity suificiently low to maintaln the catalyst in saidzone in a pseudo-liquid condition characterized by the relatively high concentration of the catalyst particles therein, adding fresh powdered catalyst to said pseudoliquid dense phase at a rate adapted to maintain it and its average catalytic activity at a suitable value, withdrawing a mixture of vaporous reaction products and used catalyst from the upper part of the conversion zone and passing .the mixture into a'separating zone of large cross-sectional area approximating that of the conversion zone at right angles to the direction of vapor flow and deflecting the catalyst particles out of the direct path of Vapor flow through said separating zone whereby said mixture is separated into two phases, a lower dense catalyst phase and an upper phase consisting of the vaporous reaction products mixed with a relatively small quantity of residual catalyst, introducing an inert gas throughout said lower dense phase in amount suitable to strip hydrocarbons entrained therewith and to maintain said phase in a fiowable condition, and continuously withdrawing both said phases from the separating zone.

2. A process for continously efiecting chemical ally adding additional quantities of the powdered material to said pseudo-liquid dense phase at a-rate adapted to maintain it and its average activity at a suitable value, withdrawing a mixture of vaporous reaction products and treated solid particles from the upper part of the conversion zone and passing the mixture into a separating zone of large cross-sectional area approximating that of the conversion zone at right anbodiments of the invention described in the foregoing are illustrative of its preferred practice and that various modifications .may be made gles to the direction of vapor flow and deflecting the particles out of the direct'path of vapor flow through said separating zone whereby said mixture is separated into two phases, a lower dense solidparticles phase and an upper phase consisting of the vaporous reaction products mixed with a relatively small quantity of solid particles, introducing an inert gas throughout said lower dense phase in amount suitable to strip treated as entrained therewith and to maintain said phase in a flowable condition, and continuously withdrawing both said phases from the separating zone.

' 3. A process for continuously regenerating powdered spent solid particles having a deposit l1 relatively high concentration or the solldparticles therein. continually adding spent solid par- 7 ticles to said pseudo-liquid dense phase at a rate adapted to maintain said pseudo-liquid phase,

said mixture is separated into two phases, a lower dense solid particles phase and an upper phase consisting of the gaseous combustion products mixed with a relatively small quantity of residual solid particles, introducing an inert gas throughout said lower dense phase in amount suitable to strip gaseous combustion products entrained therewith and to maintain said phase in a flowable condition, and continuously withdrawing both said phases from the separating zone.

4. A process as defined in claim 3 wherein the velocity of the oxygen-containing stream through the regeneration zone is maintained within the range of about 1.5 to 4' per second.

5. A process for the continuous catalytic con-- version of hydrocarbons which comprises continually eflecting the following steps-introducing a catalyst in powdered condition to a catalytic conversion zone, flowing vapors of the hydrocarbons undergoing, conversion upwardly through said zone at a velocity suiflciently low to maintain the powdered catalyst in said zone in a pseudo-liquid condition characterized by the relatively high concentration oi the catalyst particles*therein, continually adding fresh catalyst to the pseudo-liquid dense phase of catalyst in said conversion zone at a rate adaptedto maintain it and the average catalytic activity of the catalyst thereiniat a suitable value, withdrawin a mixture of vaporous reaction products and used catalyst from the upper part oi the conversion zone through a constricted outlet at a high velocity relative to that maintained in the conversion zone, used catalyst being present in said withdrawn mixture in amount corresponding to that at which fresh catalyst is added to the dense phase, impinging the mixture at said high velocity against a deflecting surtace disposed in a separating zone of relatively large cross-sectional area approximating that of the conversion zone and deflecting the catalyst particles onto! the direct path of vapor flow through the separating zone whereby said mixture is separated into two phases, a lower dense catalyst phase and an upper phase consisting of the vaporous reaction products mixed with a relatively small quantity of residual catalyst, introducing an inert gas throughout said lower-dense phase in amount suitable to strip vapor or gas entrained therewith and to maintain said phase in a flowable condition, and continuously withdrawing both said phases from the separating zone, 4.

6. A process for continuously effecting chemical conversions involving contacting a gas with a solid material, whichcomprises continually efiecting the following steps-introducing the solid material in powdered condition .to a con-- version zone, flowing the gas upwardif through said zone at a velocity. sumciently'low-to maintain the solid particles in said zoneinw, pseudoliquid condition characterized by, the irelatively high concentration of the particles of ,solid ma- 12 terial therein, adding additional quantities of said solid particles to said pseudo-liquid dense phase at a rate adapted to maintain its average activity at a suitable value and: said pseudo-liquid condition, withdrawing a mixture oi! vaporous reaction products and treated solid articles from the upper part or the conversion zone through a constricted outlet at a high velocity relative to that maintained in the conversion zone, treated catalyst particles being present in said withdrawn mixture in amount corresponding to that at which additional quantities of the solid particles are added to the dense phase, passing the mixture from the high velocity outlet zone into a separating zone of relatively large cross-sectional area approximating that of the conversion zone and deflecting the catalyst particles out of the direct path of vapor flow through the separating zone whereby said mixture is separated into two phases, a lower dense phase of solid particles and an upper phase consisting of gaseous reaction products mixed with a relatively small quantity of unseparated solid particles, introducing an inert gas throughout said lower dense phase in amount suitable to strip vapor or gas entrained therewith and to maintain said phase in a flowable condition, and continuously withdrawing both said phases from the separating zone.

'7. A process for the continuous catalytic conversion of hydrocarbons, which comprises continually effecting the following stepsintroduc-- ing a catalyst in powdered condition to a catalytic conversion zone, flowing vapors of the hydrocarbons undergoing conversion upwardly through said zone at a velocity suflicientiy low to maintain the powdered catalyst in said zone in a pseudo-liquid condition characterized by the relatively high concentration of the catalyst particles therein, adding fresh catalyst to said pseudo-liquid dense phase at a rate adapted to maintain it and its average catalytic activity at a suitable value, withdrawing a mixture of vaporous reaction products and used catalyst from the upper part of the conversion zone through a constricted outlet at a high velocity relative to that maintained in the conversion zone, used catalyst being present in said withdrawn mixture in amount corresponding to that at which fresh catalyst is added to the dense phase, passing the mixture from the high velocity outlet zone into a separating zoneof relatively large cross-sectional area approximating that of the conversion zone and deflecting the catalyst particles out of the direct path of vapor flow through said separating zone whereby said mixture is separated into two phases having a horizontally extending interface therebetween, a lower dense catalyst phase and an upper phase consisting of the vaporous reaction products mixed with a relatively small quantity of residual catalyst, introducing an inert gas throughout said lower dense phase in amount suitable to strip hydrocarbons entrained therewith and to maintain said phase in a flowable condition, and continuously withdrawingboth said phases from the separating zone.

8. A process for the continuous catalytic conversion of hydrocarbons which comprises continually effecting the following stepsintroducing a catalyst in powdered condition to a catalytic conversion zone, flowingv vapors oi the hydrocarbons undergoing conversion upwardly through said zone at a velocity sufllciently low to maintain the powdered catalyst in said zone in a pseudo-liquid condition characterized by the relatively high concentration of the catalyst particles therein, adding fresh catalyst to said pseudo-liquid dense phase at a rate adapted to constricted outlet at a high velocity relative to that maintained in the conversion zone, .used catalyst being present in said withdrawn mixture in amount corresponding to that at which fresh catalyst is added to the dense phase, passing the mixture from the high velocity outlet zone into a separating zone of relatively large cross-sectional area approximating that of the conversion zone and deflecting the catalyst particles out of the direct path of vapor flow through the separating zone whereby said mixture is separated into two phases, a lower dense catalyst phase and an upper vapor phase consisting of the vaporous reaction products mixed with a relatively small quantity of residual catalyst, introducing an inert gas throughout said lower dense phase in amount suitable to strip vapor or gas entrained therewith and to maintain said phase in a flowable condition, and continuously withdrawing both said phases from the separating zone, the rate of withdrawal of the dense phase being such as to maintain the upper levelthe'reof a substantial distance below the outlet for withdrawing the vapor phase and sufflcient to reduce the catalyst withdrawn in the vapor phase to a minor amount.

9. A process for the continuous catalytic conversion of hydrocarbons, which comprises continuall effecting the following steps-introducing a powdered catalyst to a catalytic conversion zone, flowing vapors of the hydrocarbons undergoing conversionupwardly through said zone at a velocity within the range of about 1.5 to 4' per second and adapted to maintain the powdered catalyst particles in said zone in a pseudo-liquid condition characterized by the relatively high concentration of catalyst therein, adding fresh catalyst to said dense pseudo-liquid phase at a rate adapted to maintain it and its average catalytic activity at a suitable value, withdrawing a mixture of vaporous reaction products and used catalyst from the upper part of the conversion zone into a separating zone having a cross-sectional area in the direction of vapor flow adapted to maintainthe velocity of the vapor stream in said zone of the same order of magnitude as the vapor velocity through the conversion zone and deflecting the catalyst particles out of the direct path of vapor flow whereby said mixture' is separated into two phases, a lower dense catalyst phase and an upper. phase consisting of the,

vaporous reaction products mixed with a relatively small quantity of residual catalyst, introducing an inert gas throughout said lower dense comprises continually adding a finely divided powdered cracking catalyst to a vapor-catalyst cracking zone at a rate suflicient to produce and maintain the pseudo-liquid mass mentioned below, continually passing a vapor stream of the high boiling hydrocarbons upwardly through said zone at a. relatively low velocity within the range of about 1.5 to 4' per second and adapted to maintain a highly turbulent fluidized pseudoliquid mass of the powdered'catalyst particles in said zone, and then passing the vapor stream and added catalyst through a separating zone having a cross-sectional area'at right angles to the direction of vapor flow of about the same order of magnitude as the corresponding area in the contacting zone and adapted to maintain the vapor velocities in both of said zones of the same order of magnitude, continually deflecting the powdered catalyst particles out of the path of vapor flow in said separating zone to produce therein a lower dense catalyst phase and an upper phase consisting of the vaporous reaction products mixed with a relatively small quantity of residual catalyst, introducing an inert, gas throughout said lower dense phase in amount suitable to strip hydrocarbons entrained therewith and to maintain said phase in a fiowable condition, and continually withdrawing by gravity-flow catalyst particles from said flowable lower dense phase at a rate suflicientl high to thus Withdraw and separate a major amount of the continually added catalyst.

JOSEPH W. JEWELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,439,811. April 20, 1948. JOSEPH W. JEWELL It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 3, line 28, for the word fine read finely; line 53, before pseudo and after liquid insertquotation marks; column 8, line 24, for inlet read outlet; column 9, line 30, for correponding read corresponding; line 50, insert a period after bafiie 46; column 10, line 11, claim 1, for the catalyst read the powdered catalyst; line 14, same claim, after fresh strike out powdered; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 22nd day of June, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

